Service Worker of the shopping24 hacking days wohnklamotte prototype

serviceworker_wk.js

/**
 * KH: Warning! This is part of a prototype made during our early 2016 hacking days and is not suitable for production!
 */

const VERSION = 's24-wokl-social-v6'

const CACHE_FILES = [
    '/',
    '/index.html',
    '/public/css/card.css',
    '/public/css/header.css',
    '/public/css/mainSection.css',
    '/public/css/refreshButton.css',
    '/public/img/icon.png',
    '/public/img/logo.png',
    '/public/img/twitter.png',
    '/public/img/facebook.png',
    '/public/img/instagram.png',
    '/public/js/app.js',
    '/manifest.json'
]

self.addEventListener('install', event => {
    console.log('Installing ServiceWorker with version: ', VERSION)
    event.waitUntil(
        caches.open(VERSION)
        .then(cache => cache.addAll(CACHE_FILES))
    )
})


self.addEventListener('activate', event => {
    console.log('ServiceWorker got activated.')
    event.waitUntil(
        caches.keys()
        .then(keylist =>
            Promise.all(
                keylist.map(key => {
                    if (key.startsWith('s24-wokl-social-') && (key !== VERSION)) {
                        console.log('Delete Cache: ', key)
                        return caches.delete(key)
                    }
                })
            )
        )
    )
})

self.addEventListener('fetch', event => {
    // will be overwritten if a match is found in cache
    let response

    // do not try to read third party urls from cache
    if (!event.request.url.startsWith('http://localhost')) {
        return fetch(event.request)
    }

    event.respondWith(
        // try to respond cached assets
        caches.match(event.request)
        .then(r => {
            response = r
            // KH: "I don't understand this,
            // before returning the cached asset, put it into cache?"
            caches.open(VERSION).then(cache => {
                cache.put(event.request, response)
            })
            // return the cached asset
            return response.clone()
        })
        // if something goes wrong, simply fetch the original request
        .catch(err => fetch(event.request))
    )
})